The Slatest

Do Animals Love Bacon and Doughnuts As Much As People Do?

If not, what’s wrong with them?

Donut and bacon strips overlaid with a blueprint.
Photo illustration by Slate. Photo by Thinkstock.

The National Park Service proposed on Tuesday to eliminate a 2015 rule that prohibited the use of bacon, doughnuts, and other foods as bait while hunting brown and black bears on public lands in Alaska. Meanwhile in Michigan, authorities are deploying 900 pounds of bacon and piles of doughnuts as enticements for a bear population survey that begins this weekend. Humans love bacon and doughnuts. Bears love bacon and doughnuts. Are there any animals that don’t love bacon and doughnuts?

Yes, they do exist. A capacity for tasting sweet and meaty flavors is widespread across vertebrate species and relies on genes that date back several hundred million years on the evolutionary tree. Among mammals that consume both plants and animals (as humans and bears do) these genes remain intact. Mice and rats, for example, will binge and grow obese when presented with chocolate chip cookies, salami, cheese, and condensed milk. Yet at some point along the way, certain mammals with more specific diets have shed the ability to detect the sweetness of a jelly doughnut or to savor the umami flavor in a strip of bacon.

Dedicated meat-eaters like the cat, lion, cheetah, tiger, and hyena are known to have lost the gene for tasting sugar. Bamboo-eating pandas, on the other hand, have retained their sweet receptors but no longer taste umami. Certain other animals, including sea lions and bottlenose dolphins, now lack the capacity to taste both sweets and umami. (That may be on account of their propensity to swallow prey whole. The saltiness of seawater, which masks other flavors, could also be a factor.) Vampire bats also happen to be numb to sweet and umami flavors too, this despite the fact that blood contains some sugar.

Some types of fish—the guppy and the roach, for example—are drawn to sugar, as measured by the frequency with which they’ll snap at food or hold it in their mouths. Other fish are not. The same is true of lizards. Many birds, which descend from meat-eating theropod dinosaurs, lack the gene for tasting sweetness, though in some species—like the nectar-thirsty hummingbird—the umami receptor has been adapted and repurposed for detecting sugar. Penguins are like dolphins and sea lions: They lack both sweet and umami receptors. Hard-wired tastes can also change on human time scales: Some populations of cockroaches have adapted their biology in response to sweetened poison baits, for example, such that they now find sugar unappealing.

Hunters don’t necessarily add doughnuts to their baits because bears love them more than any other food. Rather, day-old doughnuts happen to be very cheap, which makes them an economical bear-luring device. Hunters are also prone to baiting bears with corn, cookies, and candies; in lieu of bacon, some use rendered animal fat, fryer oil, ham, or baked chicken. (Hunters have also reported using peanut butter, molasses, syrup, cantaloupes, and strawberry daiquiri mix.) According to a 2014 report on bear-baiting published in Down East (the “Magazine of Maine”), bears will only bother eating hunters’ pastries and greasy slops when their normal dietary staples—berries, beechnuts, acorns, and the like—are nowhere to be found.

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Explainer thanks Gary K. Beauchamp of the Monell Chemical Senses Center.